Furuno 851 MARK-2 - Manual (Page 24)

3-1
3. ADJUSTMENT
3.1 Checking magnetron heater voltage
Magnetron heater voltage is formed on the MD Board (03P9235) of the antenna
unit, and is preadjusted at the factory for use with any length of signal cable.
Therefore no adjustment is required. However, check magnetron heater voltage
as follows:
1. Turn on the radar and leave it in stand-by.
2. Open the antenna cover.
3. Unfasten four screws to remove the RF section cover.
ELECTRICAL SHOCK HAZARD
This check is done with the
power on

DO NOT touch
the magnetron.
DANGER
Four screws
Magnetron
Figure 3-1 Antenna unit, cover opened
4. Connect a multimeter, set to 10 VDC range, between test point J825#4 and
J825#6 (GND) on the RTB Board (03P9249).
Measure voltage
at this connector
(J825).
Figure 3-2 Antenna unit, cover opened
5. Confirm the meter reads 7.6 V
±
0.1 V.
6. Close the antenna cover and tighten the cover fixing screws.